Antennas, which are integrated in a chip package e.g. together with a radio frequency (RF) frontend, are common used in radar applications such as radar distance and velocity sensors. Particularly in the automotive sector, there is an increasing demand for radar sensors used in so-called “adaptive cruise control” (ACC) or “radar cruise control” systems. Such systems may be used, for example, to automatically adjust the speed of an automobile so as to maintain a safe distance from other automobiles or other objects ahead.
Modern radar systems make use of highly integrated RF circuits, which may incorporate all core functions of the RF frontend of a radar transceiver in one single package (single chip transceiver). Such RF frontends may include, inter alia, a voltage controlled oscillator (VCO), amplifiers such as power amplifiers and low noise amplifiers (LNAs), and mixers to down-convert the RF signals into a base band or an intermediate frequency (IF) band. Furthermore, the single chip transceiver may include one or more antennas, which is thus referred to as antenna-in-package (AiP). Besides the antennas and the RF frontend also the analog base-band signal processing chain may be included in the same chip package. Therefore, these highly integrated RF transceivers as used, for example, in radar sensors, are referred to as system-in-package (SiP).
Radar applications used in automobiles are subject to various standards concerning road traffic safety, for example the functional safety standard ISO 26262 titled “Road vehicles—Functional safety”. To ensure a proper function of a radar sensor, the RF transceiver chip may be subjected to various tests at the end of the production process (end-of-line test, EOL test). The electromagnetic performance of the RF transceiver and the antennas is of particular interest. However, it seems as if no satisfying approaches for testing systems-in-package (SiP) including a monolithic microwave integrated circuit (MMIC) as well as an antenna-in-package (AiP) exists. According to known approaches, the SiP is soldered to a printed circuit board (PCB) for testing, and tests are made using the complete module, which includes at least the SiP and the PCB board. However, such an approach is not suitable for EOL tests.
In view of the above, there is a need for a device, a system and a method which allow for improved EOL testing of the electromagnetic performance of integrated RF transceivers with integrated antennas (AiP).